Process of treating wood-pulp.



PATENTED OCT. 24, 1905.,

W. A. HALL.

PROCESS OF TREATING WOOD PULP.

APPLICATION FILED DEC. 29, 1904.

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PATENTED OCT. 24, 1905.

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W. A, HALL. PROCESS OF TREATING WOOD PULP.

APPLICATION FILED 13110.29, 1904.

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STATES PATENT OFFICE,

WILLIAM AUGUSTUS HALL, OF BELLOVVS FALLS, VERMONT.

PRUCESS QF' TlqEl tTlNG WOOD-PULP.

Specification of Letters Patent.

Patented Oct. 24, 1905.

Application filed December 29, 1904. Serial No. 238,760.

1e all whom it may concern:

Beit known thatI, WILLIAM AUGUSTUS HALL, a citizen of the United States,residing at Bellows Falls, in the county of Windham and State ofVermont, have invented or discovered certain new and useful Improvementsin Processes of Treating l/Vood-Pulp, of which the following is aspecification, reference being had therein to the accompanying drawings.

In the manufacture of paper from Woodpulp it is at present customary toship, the

pulp fiber or paper-stock from the pulp-mills (which are usually locatedconveniently accessible to the timber from which the pulp is made) tothe paper-mills (which are frequently located at long distances from thepaper-mills and nearer to the consumers of the paper) in a wet conditionand in heavy sheets. This is a serious disadvantage in the manufactureof paper from wood-pulp in that the pulp when shipped wet from thepulp-mills contains a large percentage of water, and being thusunnecessarily heavy requires the payment of excessive freight rates,which in transporting this wood-pulp at long distances is a veryburdensome tax to the manufacturers. Further more, this wet wood-pulpwhen shipped in the winter time freezes and it is very difficult toremove it from the cars in this frozen condition and difficult andexpensive to thaw out; also, this wet wood pulp when shipped in summertime or if allowed to stand in storage for any great length of time atany season of the year dries together very hard on the outside of thepackages or bales, the thick sheets of pulp coming from the rolls of thewet machines shrinking into compact board like masses, which cannot bereadily disintegrated by the beating-engine, and the wet pulp is apt tomold on the insides of the packages or bales, making black spots orresulting in objectionable discolorization; also, in shipping the pulpin wet condition it becomes readily soiled, as dirt and cinders have anatural tendency to adhere to it.

The present invention has for its object to obviate the difiicultiesreferred to by a novel process of treating the wet pulp in such a mannerthat it will be practically dry before it leaves the pulp-mills and canbe readily compressed into compact bales, and thus the cost oftransportation of the pulp will be greatly lessened and the otherobjections, as above noted, incidental to shipping the pulp in wetcondition will be avoided. This object is effected by drying the wetpulp in' broken sheets or shavings by subjecting the pulp successivelyto the action of a series of steamheated rolls until it is practically,but not absolutely, dry, as it has been discovered that the hot rollswill not injure the fiber of the pulp if a very small percentage ofwater still remains therein. In other words, the pulp is not injured bydrying at high temperatures, if the drying operation be continued onlyup to the point where the pulp still contains a very small percentage ofmoisture, though apparently or practically dry.

In the accompanying drawings, Figure 1 is a sectional elevation of anapparatus by which the invention may be carried into effect, and Fig. 2is a somewhat dilferent form of apparatus from that shown in Fig. 1 bywhich the invention may also be carried into effect.

Referring to the drawings, 12 denotes a tank for holding thefinely-ground wood-pulp as it comes from the grinders and which containsa large percentage of water. In the tank 12 rotates what is known as themold, which is a perforated or foraminous roller 13, connected with aninterior suction apparatus, which draws the water from the pulp to theinterior of the roll and causes the pulp to accumulate on the surface ofthe roll, from which it is taken by an endless felt apron 14, which ispressed in contact with the roll 13 in such a manner as to take aconstantly-accumulating thin sheet of wet pulp from the moldroll 13 andcarry itover a couch-roll 15,whence it passes between a pair ofpressing-rolls 16 and 17, which remove the surplus water from the pulpand which are mounted in a suitable frame 18, and which pressing-rollsare yieldingly forced together in any suitable manner by means ofadjustable bearings, which may be regulated, as by means of hand-wheelsand screws, as shown in the drawings, to suit different conditions ofwork.

In passing the wet wood-pulp between the pressing-rolls 16 and 17 on theapron 14 the pulp adheres to the top roll 16 and is taken off the apron.In thus treating the pulp it has heretofore been customary to allow acomparatively thick sheet of pulp composed of a series of thin layers orwindings to accumulate on the top roll 16 by successive rotations ofsaid roll, and such thick sheets were then out so as to be removed fromthe roll and were folded and bundled together for transportation, andthese thick sheets, if partly or IIO constantly removed in thin brokensheets or shavings from the top roll 16 of the wet machine by astationary knife or doctor 18 and falls down again onto the endlessapron 14, so as to be carried to a second endless apron 19, preferablyof canvas. The apron 19 passes over a series of hot rolls 20, preferablyheated by steam in a well-known manner, and each of which, into contactwith which the broken sheets or shavings of dried pulp are carried bythe endless apron 19, is provided with a stationary knife or doctor 21,which will remove the pulp from these rollers as it passes around thesame and cause it to fall upon another part of the apron in such amanner as to be carried to the next succeeding hot roll. The hot moistpulp is broken up or opened out more or less after passing around eachhot roll, so that the moisture can the more readily escape therefrom inthe form of steam, and the drying process is thus expedited. A suitablenumber of heated rolls 20 will be provided, so that when the pulp haspassed around the last roll of the series it will be practically orapparently, but not absolutely, dry.

In connection with the drying rolls or cylinders 20 and the endlessapron 19, cooperating therewith, a continuous baling-press 22 ofwell-known structure and operation is preferably provided and into thehopper 23 of which the dried shavings or pulp may be delivered, so thatin one continuous operation the pulp coming from the tank 12 will bedried and then compacted into bales for convenient transportation.

In the form of the apparatus shown in Fig. 2 a series of separateconveyers 2 1 are preferably provided,in connection with the dryingrolls20, about which passes the endless canvas apron or carrier 19. In thisform of the apparatus hooded doctors 25 are provided for removing thepulp from the drying-rollers 20 and causing it to fall upon thesuccessive endless carriers 24:.

Having thus described my invention, 1 claim and desire to secure byLetters Patent 1. The herein-described process of treating form of thinbroken sheets or shavings, and in this drying operation successivelybreaking up the sheet or mass of pulp as it comes from each heateddrying-roll, and then immediately compressing these dried broken sheetsor shavings into bales for convenient transportation".

2. Theherein-described process of treating wet wood-pulp, consisting insubjecting a noncontinuous or broken-up sheet thereof to the successiveaction of a series of hot dryingrolls until the pulp is nearly orpractically dry, the sheet or mass of pulp being successively broken upor disintegrated after passing each heated roll to permit the readyescape of steam therefrom.

3. The herein-described process of treating wood-pulp, for paper-stock,consisting in breaking up a sheet of wet pulp after the same passes thedevices which remove the surplus water therefrom, and then subjectingthe non-continuous or broken sheets of pulp to the successive action ofa plurality of drying-rolls, until the pulp is nearly or practicallydry, and, in this drying operation, successively breaking up ordisintegrating the massof pulp as it is removed from each drying-roll,to facilitate the ready escape of steam from the hot moist pulp.

4E. The herein-described process of treating wood-pulp, for paper-stock,consisting in breaking up a sheet of wet pulp after the same passes thedevices which remove the surplus water therefrom, then subjecting thenon-continuous or broken sheet of pulp to the successive action of aplurality of dryingrolls, until the pulp is nearly or practically dry,and, in this drying operation, successively breaking up ordisintegrating the mass of pulp as it is removed from each dryingroll,to facilitate the escape of steam, and finally compressing the driedpulp into bales by a baling-press into the hopper of which the driedpulp is passed directly from the drying apparatus: whereby, at onecontinuous operation, the pulp is dried in a brokenup condition andcompressed into bales for convenient transportation.

1n testimony whereof I affiX my signature in presence of two witnesses.

WVILLIAM AUGUSTUS HALL.

\Vitnesses:

HENRY OALVER. GERTRUDE M. STUGKER.

